The ICP-AES technique and experimental design were employed to precisely determine the content of strontium in high Ca/Sr ratio oil field brine of Qaidam basin (Qinghai province, western China). From the statistical analysis using six factor factorial, it was found that Ca2+ is the significant interfering element for the recovery of strontium. Accurate strontium content was derived by eliminating the interference contribution according to the influencing model. The experimental results indicate that, under optimal conditions, the ICP-AES method for strontium determination has low LOD and LOQ, and the precision and accuracy are good with the relatively standard deviation below 1% and recovery between 98.0% 105.0%.